This disclosure relates generally to medical devices and methods, and in certain of its aspects more particularly to catheter systems and associated methods which can be used for example in the delivery of cells to a patient.
In established and developing medical therapies, the administration of a therapeutic agent, such as a flowable medium containing cells, is often necessary. The therapeutic agent may be administered for example to treat an acute or chronic disease or condition. In these respects, the therapeutic agent may be introduced into tissue in any of a variety of regions in the patient. Oftentimes, the tissue is tissue of a solid organ such as the heart, kidney, liver, pancreas, spleen, intestine, skeletal muscle, bone, lung(s), reproductive organs, or brain.
One illustrative area of interest involves heart disease. Over 1.1 million people experience a myocardial infarction each year in the United States. These events occur because of oxygen deprivation due to a reduction in the oxygenated blood supplied to the myocardium (heart muscle tissue). Traditionally it was believed that damage to cardiomyocytes (heart muscle tissue cells) was permanent because of the absence of effective cardiac progenitor cells which are able to replace dead or damaged cardiomyocytes. Cardiomyocytes were thought to be terminally differentiated cells having lost their ability to naturally proliferate shortly after birth.
More recent work suggests that the human heart may in fact be capable of regenerating cardiomyocytes following injury to the myocardium. This has led to the proposal of various cell therapies seeking to strengthen or regenerate damaged myocardium to improve performance in the infarcted region. Treatment goals vary widely but generally fall into the categories of replacing dysfunctional, necrotic, or apoptotic cardiomyocytes with new functional cells (thereby decreasing infarct size and improving cardiac output), increasing the quality and quantity of contractile tissue, and promoting local angiogenesis (creation of new blood vessels). In order to achieve these goals, various therapies have been developed involving the delivery of different types of cells into the infarcted myocardium by various means with varying degrees of limited success depending on the circumstances and the method used.
One technique for delivering cells into the infarcted region of the myocardium is by retrograde perfusion from within a cardiac vein. With this technique, a vein opposite, or in the area of, an artery in the infarcted region is temporarily occluded using an expanding balloon catheter or similar device while a treatment agent containing the cells is introduced into the vein. The vein remains occluded during perfusion of the treatment agent to allow the treatment agent containing the cells the opportunity to be delivered into the capillaries of the tissue in the treatment region. The coronary sinus is a common entry point for this procedure because it is easily accessed from either the superior or inferior vena cava, and because venous pressures in the coronary sinus are significantly lower than arterial pressures making it more likely the treatment will succeed with less risk to the patient.
While delivery of cells to the heart as discussed above has received significant attention, many proposals and methods are also known for treating other diseased organs or tissue areas, such as those named above, with cells or other therapeutic agents.
There remain needs in this area for safe and effective devices, apparatuses, systems and methods for the delivery of cells and/or other substances into patient tissues.